Rotary switch for use in automatic telephone systems



J. M. UNK

Jan. 11 1955 ROTARY SWITCH FOR USE IN AUTOMATIC TELEPHONE SYSTEMS Filed Dec. 1, 1950 3 ,suansaea mine/e12 15 .a a? .34 a

INVENTOR.

JACOB MA RINUS UNK AGENT United States Patent ROTARY SWITCH FOR USE IN AUTOMATIC TELEPHONE SYSTEMS Jacob Marinus Unk, Hilversum, Netherlands, assignor to Hartford National Bank and Trust Company, Hartford, Conn., as trustee Application December 1, 1950, Serial No. 198,571

Claims priority, application Netherlands December 16, 1949 4 Claims. (Cl. 17927.51)

The present invention relates to rotary electrical switches and more particularly to those of the type adapted for use in automatic telephone systems.

Automatic telephone systems may be equipped with switching apparatus comprising a stationary part having a great number of fixed contacts arranged side by side in different layers, and a movable part comprising one or a plurahtyof wiper groups by which the fixed contacts are wlped in succession. The stationary part is generally termed the contact bank and the movable part is referred to as the wiper carriage. In connection with switches comprising a rotary movable part, the term rotor is sometimes used. The invention relates to switches of the lastment1oned type. They will hereinafter be termed rotary switches.

Fairly elaborate automatic telephone systemscomprise hundreds of such rotary switches. They are arranged in groups of 20 to 30 as closely as possible side by side in the direction of length of a frame, the shafts of the rotors of such a group extending in line with one another. Such a grouping does not easily permit replacement of one swltch by another and therefore it is customary to make the switches so that the movable members wear out sooner than the stationarymembers, and in the case of repair, it is mainly the movable part which needs to be renewed.

Constructions are known in which the rotor can be removed without the need of changing the position of other parts. In this case, the parts jointly constituting the switch are fitted between two slotted side plates carrying the rotor shaft which is clamped by means of nuts provided at its ends.

ln another construction the rotor together with its driving mechanism and further auxiliary members cooperating with the rotor are fitted between two separate plates. This composite member, which may be termed a rotary set, is secured to the stationary part by connecting the plates of the rotary set to those of the contact bank. This connection is established by means of lateral fastening means.

Since the switches are arranged as closely as possible side by side in the frame, the lateral fastening means are only accessible with difiiculty. Moreover, they increase the required space. As an alternative, the rotor shaft has been secured to the side plates with the use of countersunk screw joints. In this manner projecting parts are avoided but the plates must then be thicker, hence the size of the switch is not materially reduced.

When replacing the rotary set of a defective switch, it is of importance that the traffic should be interrupted for a minimum period of time. This requires easily accessible joints adapted to be readily loosened and restored.

According to the invention the said disadvantages are obviated and at the same time the last-mentioned condition is fulfilled. It concerns a rotary switch comprising a contact bank fitted between two plates and a rotary set constituted by a rotor with wipers, which is movable about a shaft and fitted, together with its driving means, between two additional plates. According to the invention, on assembling the contact bank and the rotary set, each of the two ends of the rotor shaft is clamped between one plate of the contact bank and one plate of the rotary set.

According to the invention the rotary set may be rapidly fitted and removed by providing one of the plates of 2,699,468 Patented Jan. 11, 1955 the contact bank with a stationary and a movable arm which constitute a pair of tongs having a movable and a stationary jaw, one of the plates of the rotary set comprising a stud arranged parallel to the shaft and clamped between the two jaws and the movable arm exerting a force on the stud, which produces a resultant pressure directed to the rotor shaft.

In the positions of rest the wipers of the rotor must each engage a stationary contact of the contact bank. If the driving mechanism of the rotor consists of an electromagnet, the armature of which comprises an armature arm with a pawl which co-operates with a ratchet wheel of the rotor, the latter is driven stepwise when the magnet is repeatedly energized and de-energized. By slightly shifting the stud relatively to the plate of the rotary set to which it is secured, in a direction at right angles to the plane through the stud and the rotor shaft, it is possible to adjust the position of the rotor wipers on the stationary contacts in the rest position, since the rotary set is rotated about the rotor shaft by this adjustment. This can be effected without loosening the clamping joint, whereby the accurate adjustment of the rotor, the shaft of which already occupies its prescribed position, is facilitated.

In order that the invention may be more clearly understood and readily carried into effect, it will now be described in detail with reference to the accompanying drawing, in which:

Figs. 1 and 2 are plan and elevational views respectively of one embodiment of the rotary switch according to the invention.

The rotary switch comprises a contact bank 1, which is fitted between two side plates 2, and a rotary set comprising side plates 3. The plates 2 are provided with bentover tags 4 to secure the switch to a frame accommodating a number of such switches. The contact bank coinprises six rows of contact studs 5. These rows are separated from one another by insulating material, in which the contact studs are so secured as to be insulated from one another.

On the shaft 6 of the rotary set a rotor is seated, which comprises two sets of wipers 7 and 8 insulated from each other. The contact wipers of each set are also insulated from one another. For this purpose the rotor drum 9 is made of insulating material. This drum is rotatable about the rotor shaft 6 and actuated by a driving device. The figures show a switch comprising individual and complete driving means. The rotor drum 9 provided with wipers 7 and 8 is driven stepwise by the armature 10 of the electromaguet 11. When the electromagnet 11 is energized, the armature 10 rotates about the armature shaft 12. The end of the armature arm moves over such a distance that the pawl 13 engages the next following space of the ratchet wheel 14. Upon de-energization of the electromagnet 11 the armature arm is retracted by the spring 15. Thus the toothed wheel 14 and consequently the rotor are turned by one step. The driving device is secured to one of the side plates of the rotary set.

The relative spacing between the wipers of each set is double the spacing between the rows of contact studs. Since, however, the two sets of wipers 7 and 8 change their positions, one set engages the rows of contact studs located between the rows wiped by the other set. The rotor is furthermore provided with a circular numerated are 16, the position indicator, on which the contact set engaged by the wipers is read.

By joining the contact bank and the rotary set the rotor shaft is clamped between the side plates 2 and 3. To this end, the latter are provided the recesses 17 and 18, so that the position of the shaft is accurately determined. In order to prevent, upon dismounting, the shaft and the rotor from being loosely located in the rotary set, resilient strips 19 and 20 are provided on either side of the rotor. They are secured to the shaft and provided with a stud 21 which extends in an aperture in the side plates 3 of the rotary set. Since the stud has a small amount of play in this aperture, the attachment of the shaft between the side plates is not hampered by these springs.

For securing the two parts to one another provision is made of a stationary arm 22, which is located approximately in the symmetry plane between the plates 2 of the contact bank and secured to one of these plates through a transverse wall 23. The end of the arm 22 has an end surface 24 which is directed approximately to the shaft of the rotary set. A part 25 of one of the side plates 3 of the rotary set is provided with an upright stud 26. which rests against the end surface 24 of the arm 22 when the rotary set and the contact bank are joined. By means of a movable arm 27 which is connected to the stationary arm 22 by being pivotally carried by the stud 25, the stud 26 is pressed against the surface 24, a resultant pressure directed approximately towards the shaft 6 being produced under the action of the force exerted by the pressure surface 29 of the arm 27 on the stud 26. The movable arm 27 is provided with a grip 30. The spring 31 maintains the pressure of the arm against the stud 26.

The upright stud 26 is secured to a separate plate 32 which is secured by screw bolts to the arm 25. This plate 32 is rotatable through a small angle about the bolt 33, since a slot-shaped aperture 35 for the bolt 34 is provided in the plate. Thus a slight rotational adjustment of the rotary set about the shaft 6 is possible and the position occupied by the wipers 7 and 5 in the rest position of the rotor on the stationary contacts 5 of the contact bank is adjustable.

The side plates of each of the two parts are interconnected through transverse walls 36, so that each part constitutes a rigid assembly. For the attachment of the contact bank use is made of plates 37 which are bent over at right angles and secured by means of screws 38 to the side plates and to the contact bank.

Instead of providing the switches with individual driving means, a number of switches arranged side by side may be driven by a common device, the rotors of the switches, as long as they are required to rotate, being individually coupled by a coupling mechanism to the main shaft operating the switches. The invention also relates to switches driven in this manner.

What I claim is:

1. A rotary switch for use in automatic telephone systems and the like comprising a stationary part provided with two parallel plates and a contact bank mounted therebetween, a removable rotor unit provided with a framework having two parallel plates, a rotatable wiper assembly provided with a rotor shaft and adapted to cooperate with said contact bank, and means for imparting rotation to said wiper assembly, further characterized in that said rotor shaft bears with its ends against an edge of the plates of the rotor unit framework, said plates and the plates of the stationary part being equally spaced, so that in the assembled state in which the corresponding plates of the stationary part and the rotor unit are flush with one another, the rotor shaft is rigidly clamped at both ends between opposing edges of the corresponding plates.

2. A rotary switch assembly, as set forth in claim 1, further characterized in that said shaft is provided with strips which rest resiliently against the inner side of the plates of the rotary set and are provided with a stud extending into an aperture in the plates of said rotary set, said aperture having a dimension permitting a limited shift of the shaft.

3. A rotary switch assembly, as set forth in claim 1, including means for removably coupling said rotor unit to said stationary part, said coupling means comprising a stud secured to one plate of said framework and extending parallel to said shaft, a pair of tongs secured to one plate of said stationary part and provided with a movable jaw and a stationary jaw for clamping said stud, and a spring connected between said movable jaw and said one plate of said stationary part and urging the movable jaw to exert on the stud a force which produces a resultant pressure directed to the rotor shaft.

4. A rotary switch assembly as set forth in claim 3, including means to effect shifting of said stud at right angles to the plane passing through the stud and the rotor shaft relative to the plates of the rotary set, whereby the position occupied by the wipers of the rotor in the rest position on the contacts of the bank are adjustable. 

